Rewiring Headlamps

[MICAH1]

This is my second GT and like most on this site, it is past time to refresh the wiring to the left and right headlamps. After gently stripping the tape wrapping off of the wiring on the driver's side under the hood, I notice that only the ends (last six to eight inches to bulbs on both sides have lost their insulations. I have purchased about ten feet of 12 gauge auto wire that just happen to be bonded together with the same colors (yellow, white, brown) as the GT. Since the wiring under the hood is in such great condition, I have decided to replace only the last twelve inches or wire to the lights. For those who have replaced the entire length from the bulbs to the fuse box, can you tell me if the brown wire from the three prong headlamp connectors is grounded somewhere in the lamp assembly, or does it run to the fuse box and ground there??

[namba209]

Thomas, both brown wires from the headlights are grounded at one of the two sheetmetal screws forward of the radiator support outboard of the brake MC. Those two screws ground all the front end accessories. HTH.

[kwilford]

DO NOT just replace the end of the headlight wiring. Why? Because under the pretty tape, right back to the splice in the engine compartment where the fuse wire changes from plastic insulation to rubber and the wires split in two (to feed left and right sides, high and low beams), the insulation is rotten. Read any number of threads at
http://www.opelgt.com/forums/2c-gt-h...emoval-repair/
and also look at the photos at
http://www.opelgt.com/forums/2c-gt-h...ring-hell.html
and you will see what I mean

[tomking]

Kieth is right on. Dont do it. Go all the way back to where the ground wires are and you will see a splice. Begin there. You risk burning your treasure up otherwise.

[opelgtguy]

Make sure you replace the wiring back to the spot above the front tire where the rubberized insulation splices into the normal plastic insulated wire.
I swore my wiring was great, because the car had been garage-kept it's entire life. Wow - was I wrong I've made a display board with my old, cracked wiring and connector plugs attached, that I take to Carlisle every year as proof to others
Rick Gradwell

[baronbors]

The insulation on my 71's headlights looked good but crumbeled just by touching it all the way back to the firewall so it ALL went bye-bye

[Lindsay]

Years ago, I had a heck of a time finding heavy duty headlight (or is it headlamp?) connectors. Most of the auto parts stores connectors used 14 GA or 16 GA wires (wimpy).

Recently found high temp connectors with 14 GA wires at AutoZone for $10 per pair. Considering this set if I ever install better headlights. There is at least 0.5v voltage drop through the GT headlight circuit, so would need relays & rewire.

Prefer harness tape for easier (future) maintenance than wrapping entire harness with sticky electrical tape. I still like that OEM look!

[MICAH1]

Okay everyone, undid the tape from the front of the fuse box (under the hood) to the extreme right (passenger side) under the right headlamp assembly and just as Kwilford said, rotten insulation falling off the wire. But only the WHITE, YELLOW, and BROWN wires to the headlamps. All of the other wiring to the horns, turn signal lamps, side markers, and micro switches are very flexible and not faded from wear and time as the BIG THREE!! That must suggest the heat from the electrical current to the headlamps. That said, my plan is to replace the worn portions of the wires running to the left and right halogens.

By the way, I have a 1973 opel service manual with the GT color schematic. Very helpful!!!

[kwilford]

Originally Posted by MICAH1 Okay everyone, undid the tape from the front of the fuse box (under the hood) to the extreme right (passenger side) under the right headlamp assembly and just as Kwilford said, rotten insulation falling off the wire. But only the WHITE, YELLOW, and BROWN wires to the headlamps. All of the other wiring to the horns, turn signal lamps, side markers, and micro switches are very flexible and not faded from wear and time as the BIG THREE!! That must suggest the heat from the electrical current to the headlamps.

Glad I could be of help. The crumbly insulation is a different material than the rest of the wiring, and I believe it was specific to the GT, and ONLY used in that portion of the headlight high, low and ground wiring past the splice. Presumably it was to make the wiring more flexible as an allowance for the headlight rotation, but they must have been smoking some bad stuff in the lab that day , as it just plain disintegrates, even in the absence of air and light (ozone and ultraviolet).

Jarrell, could you please move this thread to the correct Forum? My days of Über-Moderating are long since done, but the desire to see order still persists Thanks!

[soybean]

Thomas, take a look at this thread, I rewired mine, it works great and lights are brighter, and with fusible links, I'm not worried about burning up the fusebox. Hth, Jarrell
http://www.opelgt.com/forums/2c-gt-h...adlight+Relays